1. Field of the Invention
An aspect of the present invention relates to at least one of a liquid ejecting head and an image forming apparatus.
2. Description of the Related Art
For an image forming apparatus such as a printer, a facsimile machine, a plotter, or a complex machine thereof, there is known, for example, a liquid ejection recording type image forming apparatus using a recording head composed of a liquid ejecting head (liquid drop ejection head) for ejecting a liquid drop of ink, for example, an ink-jet recording apparatus.
A liquid ejecting head has, for example, plural nozzles for ejecting a liquid drop, a separate liquid chamber communicated with each nozzle (also referred to as a “separate flow channel”), and a common liquid chamber for supplying a liquid to each separate liquid chamber (also referred to as a “common flow channel”), wherein a liquid in such a separate liquid chamber is pressurized by a pressure generating part such as a piezoelectric actuator, a thermal actuator, or an electrostatic actuator, to eject a liquid drop.
For a configuration of a common liquid chamber in such a liquid ejecting head, it is known that a supply port part and a discharge port part, each of which communicates with an exterior, are provided at sides of both end portions of a common liquid chamber in a direction of nozzle arrangement and a liquid is circulated in the common liquid chamber, thereby reducing retention of air bubbles (Japanese Patent Application Publication No. 2011-025663).
Furthermore, it is known that a supply port part is provided at a central portion of a common liquid chamber in a direction of nozzle arrangement and an aperture part is provided whose cross-section in a direction orthogonal to a direction of nozzle arrangement gradually decreases toward both end portions in a direction of nozzle arrangement, thereby improving a flow rate at both end portions and reducing retention of air bubbles (Japanese Patent Application Publication No. 2011-056729).
Furthermore, it is also known that positions for providing supply port parts and/or aperture parts are different among plural common liquid chambers (Japanese Patent Application publication No. 2010-158806).
Meanwhile, when a configuration is provided in such a manner that a supply port part is provided at a side of one end of a common liquid chamber in a direction of nozzle arrangement and an aperture part is provided at a side of the other end, a fluid resistance in the common liquid chamber from the supply port part to a separate liquid chamber may be greatly different between an upstream side and a downstream side of flow. Accordingly, a difference may be generated in an amount of a liquid supplied to the separate liquid chamber so as to cause a deviation in an amount of ejection between a side of one end of a nozzle sequence and a side of the other end and a variable density in a formed image.
In particular, an irregularity of density may be easily-noticeable in a case where an image with a high density such as a photographic image is formed wherein an amount of ejection per unit area increases, a case where an image is formed at a high speed wherein an amount of ejection per unit time increases, a case where a thin halftone image is formed although an amount of an ejected drop is not large, etc.